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This paper deals with the thermal, chemical and metallurgical interactions between the printed circuit board and the solder wave. Special attention is devoted to the quality of the final solder fillet as a function of each variable. The individual zones inside of a solder wave is analysed. Their effect on the printed circuit and their components is explained. Guidelines for production parameters, i.e., solder temperature, conveyor speed, depths of immersion, impedance angle, hole‐to‐wire ratio, etc., are outlined. The wave solder operation cannot be isolated from fluxing and preheating; therefore, these two additional operations are also analysed. This will be limited, however, to those aspects directly related with wave dynamics. The paper concludes with a discussion of voids and entrapment in the solder fillet as they relate to the wave soldering process. A case history is used to outline the effect of voids on quality. Suggestions are made to avoid fillet imperfections such as blow holes, voids and incomplete fillets. Proper touch‐up procedures is also covered.

This report, presented as the keynote paper at Surface Mount International, is the culmination of joint efforts to assess the use of lead in electronics assembly. The study, which is presented in two parts, involved the collaboration of the following participants: B. R. Allenby and J. P. Ciccarelli, AT&T, Basking Ridge, New Jersey; I. Artaki, J. R. Fisher and D. Schoenthaler, AT&T Bell Laboratories, ERC, Princeton, New Jersey; T. A. Carroll, Hughes, El Segundo, California; D. W. Dahringer, Y. Degani, R. S. Freund, T. E. Graedel, A. M. Lyons and J. T. Plewes, AT&T Bell Laboratories, Murray Hill, New Jersey; C. Gherman and H. Solomon, GE Aerospace, Philadelphia, Pennsylvania; C. Melton, Motorola Inc., Schaumburg, Illinois; G. C. Munie, AT&T Bell Laboratories, Indian Hill, Naperville, Illinois; and N. Socolowski, Alpha Metals, Jersey City, New Jersey. Part 1 was published in the previous issue of Circuit World, Vol. 19, No. 2.

The purpose of this study is to investigate the effect of electromigration (EM) on solder alloy joint on copper with nickel surface finish. Sn-Bi solder alloy has been used in this research.

The EM process was completed with the duration of 0, 24, 48, 72 and 96 h under direct current (DC) of 1,000 mA. Tensile stress on the substrates was assessed after EM at a tension rate of 0.1 mm/min. Microscopy was used to observe the formation and size of voids and conduct an analysis between copper and nickel substrates.

Four types of intermetallic compounds (IMCs), namely, Cu-Sn, Cu3Sn, Cu6Sn5, and Sn-Bi, were detected between the Sn-Bi/Co solder joint. Voids appear to be at the anode and the cathode for 96 h of EM for Sn-Bi/Ni solder join; however, there seem to be more voids at the cathode.

EM is one of the crucial keys to produce a good integrated circuit (IC). When the current density is extremely high and will cause the metal ions to move into the electron direction flow, it will be characterised based on the ion flux density. In this research, the effect of EM on the Sn-Bi solder alloy joint on copper with nickel surface finish was studied.

This report, presented as the keynote paper at Surface Mount International, is the culmination of joint efforts to assess the use of lead in electronics assembly. The study, which will be presented in two parts, involved the collaboration of the following participants: B. R. Allenby and J. P. Ciccarelli, AT&T, Basking Ridge, New Jersey; I. Artaki, J. R. Fisher and D. Schoenthaler, AT&T Bell Laboratories, ERC, Princeton, New Jersey; T. A. Carroll, Hughes, El Segundo, California; D. W. Dahringer, Y. Degani, R. S. Freund, T. E. Graedel, A. M. Lyons and J. T. Plewes, AT&T Bell Laboratories, Murray Hill, New Jersey; C. Gherman and H. Solomon, GE Aerospace, Philadelphia, Pennsylvania; C. Melton, Motorola Inc., Schaumburg, Illinois; G. C. Munie, AT&T Bell Laboratories, Indian Hill, Naperville, Illinois; and N. Socolowski, Alpha Metals, Jersey City, New Jersey.

For many years the analysis of contaminant residues on PWB surfaces has been of major importance to the industry. While the identification of residues left on metallic surfaces has proven to be relatively straightforward, the analysis of organic contamination of similar composition to that of the underlying board surface has not been as successful. Through the use of modern XPS instrumentation, the non‐ionic component of water soluble flux has been identified and differentiated from the chemically similar FR‐4 and soldermask substrates. This paper presents the XPS results for a series of experiments aimed at determining the location and relative concentration of water soluble flux residues on standard surface insulation resistance (SIR) comb patterns. The data show that the water soluble flux residue is not present as a uniform coating on the board surface but appears in localised sites in high concentrations while being absent in other locations. Through more aggressive cleaning procedures the sites of high residue concentration can be significantly reduced.

Visual inspection remains the dominant method of assessing component lead solderability and finished board solder joint quality. In recent years the wetting balance has received much attention as an attractive alternative to the inherently subjective visual inspection method of assessing component termination solderability. Whether direct visual inspection or wetting balance methods are used, the method can be shown to be effective only if the results are in agreement with board‐level soldering performance. This paper addresses the issue of the agreement of visual board‐level solder joint quality with both visual ‘dip and look’ solderability assessment and wetting balance measurement of the components prior to board assembly. A description of visual ‘dip and look’ solderability test assessment and of wetting balance methodology for components is presented, and a compendium of wetting balance tests and indices are documented in the Appendix. The experimental strategy employed is outlined, and details of the experimental technique (including the equipment, materials and component sample preparations) are provided. The experimental results present a comparison of both ‘dip and look’ visual solderability assessment and wetting balance measures with regard to actual board‐level soldering performance. The ability of the various assessment methods to predict board level defects is also explored.

The arrival of low solids content flux on the electronics production market represents something of a revolution. Traditionally, the electronics industry has used, and is still using, successfully rosin fluxes containing between 15% and 35% solids content, for wave soldering electronics assemblies (PTH and single‐sided PCBs). It is therefore surprising to find that today fluxes containing between 2% and 10% rosin can be both efficient and cost‐effective.

The aim of the present study was to gather and review all the important properties of the Sn–Ag–Cu (SAC) solder alloy. The SAC solder alloy has been proposed as the alternative solder to overcome the environmental concern of lead (Pb) solder. Many researchers have studied the SAC solder alloy and found that the properties such as melting temperature, wettability, microstructure and interfacial, together with mechanical properties, are better for the SAC solder than the tin – lead (SnPb) solders. Meanwhile, addition of various elements and nanoparticles seems to produce enhancement on the prior bulk solder alloy as well. These benefits suggest that the SAC solder alloy could be the next alternative solder for the electronic packaging industry. Although many studies have been conducted for this particular solder alloy, a compilation of all these properties regarding the SAC solder alloy is still not available for a review to say.

Soldering is identified as the metallurgical joining method in electronic packaging industry which uses filler metal, or well known as the solder, with a melting point < 425°C (Yoon et al., 2009; Ervina and Marini, 2012). The SAC solder has been developed by many methods and even alloying it with some elements to enhance its properties (Law et al., 2006; Tsao et al., 2010; Wang et al., 2002; Gain et al., 2011). The development toward miniaturization, meanwhile, requires much smaller solder joints and fine-pitch interconnections for microelectronic packaging in electronic devices which demand better solder joint reliability of SAC solder Although many studies have been done based on the SAC solder, a review based on the important characteristics and the fundamental factor involving the SAC solder is still not sufficient. Henceforth, this paper resolves in stating all its important properties based on the SAC solder including its alloying of elements and nanoparticles addition for further understanding.

Various Pb-free solders have been studied and investigated to overcome the health and environmental concern of the SnPb solder. In terms of the melting temperature, the SAC solder seems to possess a high melting temperature of 227°C than the Pb solder SnPb. Here, the melting temperature of this solder falls within the range of the average reflow temperature in the electronic packaging industry and would not really affect the process of connection. A good amendment here is, this melting temperature can actually be reduced by adding some element such as titanium and zinc. The addition of these elements tends to decrease the melting temperature of the SAC solder alloy to about 3°C. Adding nanoparticles, meanwhile, tend to increase the melting temperature slightly; nonetheless, this increment was not seemed to damage other devices due to the very slight increment and no drastic changes in the solidification temperature. Henceforth, this paper reviews all the properties of the Pb-free SAC solder system by how it is developed from overcoming environmental problem to achieving and sustaining as the viable candidate in the electronic packaging industry. The Pb-free SAC solder can be the alternative to all drawbacks that the traditional SnPb solder possesses and also an upcoming new invention for the future needs. Although many studies have been done in this particular solder, not much information is gathered in a review to give better understanding for SAC solder alloy. In that, this paper reviews and gathers the importance of this SAC solder in the electronic packaging industry and provides information for better knowledge.

This paper resolves in stating of all its important properties based on the SAC solder including its alloying of elements and nanoparticles addition for further understanding.

The purpose of this paper is to publish on the review of the lead free solder for electronic packaging. This involved the basic principles of the solder, the lead solder and its legislation and the lead free solder with its mechanism. In addition, this paper also reviews on the lead free solder characteristics that focused on its wettability.

This paper approach on the review of the solder wettability on the surface. It reviews on the solder especially on the contact angle and surface tension that is covered under the wettability of the solder.

This paper also reviews on the lead free solder characteristics that focused on its wettability.

This paper summarized finding from other researchers. The authors collect and summarize the useful data from other papers or journals. It is to create an understanding for the reader by discussion from the others research papers findings.

In Part 1, background information on mechanical properties and metallurgy of solder alloys and soldered joints has been presented. In Part 2, mechanisms of damage and degradation of components and soldered joints during soldering, transport and field life have been discussed, the most important mechanism being low cycle fatigue of the solder metal. In this third part, the determination of the fatigue life expectancy of soldered joints is discussed. Accelerated testing of fatigue is needed, as the possibilities of calculations are strongly limited. A temperature cycle test under specified conditions is proposed as a standard. A model is worked out for the determination of the acceleration factor of this test. A compilation of a number of solder fatigue test results, generated in the author's company, is presented.